The present invention relates generally to a dispensing closure for containers and more particularly to a two piece dispensing closure, wherein a hinged lid is moved from a base of the closure to uncover an orifice through which the container contents are dispensed. This type of closure is made from molded plastic and used extensively in dispensing food products, such as salad dressings, and for personal care and household products.
The typical dispensing closure for a container comprises a generally circular base with a dispensing orifice in the front section of the upper surface and an annular skirt depending downwardly from the upper surface that is adapted to engage and secure the base to the container, usually by means of internal threads that are screwed onto the neck of the container. A lid having a plug on its underside for sealing the dispensing orifice is adapted to be pivotally moved with respect to the base to be opened and closed by the pressure of the finger or thumb.
In many instances the base and lid of the closure are molded as a single unit, the lid being connected to the base by a flexible hinge, which is known in the industry as a "living hinge". A disadvantage of the "living hinge" is that the hinge portion of the closure has a tendency to crack, and eventually break, separating the lid from the base. Also, when the lid is rotated from the open position, it reaches a point from which it tends to snap rapidly to the closed position, and can splash liquid product, or even catapult one or more drops toward the user's face or clothing, thus presenting some danger if the product is an irritant.
Moreover, in the "living hinge" design, at least a portion of the hinge necessarily extends beyond the circumferential periphery of the closure of the rear of the base and creates problems during the assembly line filling of the container in that such an eccentric shape is subject to bumping and breakage, and can interfere with the highly automated equipment used during assembly of the closure and container of the product to be marketed.
The "living hinge" design has been replaced to some extent by a dispensing closure design where the base has a notch located at the approximate center of top, and a relatively narrow rectangular channel extends from the notch to the front edge of the base with a dispensing orifice positioned in the channel proximate the front edge. A lid having a generally flat upper surface which terminates in a downwardly depending flange and indented end pieces is adapted to be received in a snap-fit into the notch, and when rotated to the closed position, lies entirely within the channel. The underside of the lid has an annular plug which mates with, and seals the orifice. The lid is maintained in the open position by means of an interference fit between the bottom edge of the flange and lugs located at the forward edge of the bottom of the notch where it intersects the rear of the channel. The lid is maintained in the notch in the open position by contact between a groove in the leading edge of the flange and a tab protruding upwardly from the intersection of the front wall and bottom of the notch.
Another type of dispensing closure has been developed where the base and a dispensing nozzle, or spout, comprise two separate components that are interconnected through a modified ball and socket joint, or protruding pin or post from one component mating with a corresponding recess in the other component to form a pin/recess hinge structure between the two components. In one form of the pin/recess hinge design, the outer surface of the base of the closure has a notch formed therein, said notch being shaped to receive one end of a hollow dispensing type nozzle of lid which has a passageway for the liquid product. In the fully open position the nozzle communicates with the inside of the container by means of an orifice through the base located in the bottom of the notch. The nozzle end portion mates in a modified ball and socket configuration when press fit into the notch in the base. This latter ball and socket hinge design further relies upon a key-slot configuration in the notch of the base and the portion of the dispensing nozzle to be disposed within the notch, respectively, to limit the open position of the dispensing nozzle type lid, as well as interfering projections on the forward face of the notch and on the portion of the nozzle disposed within the notch to maintain the nozzle in an open position during the dispensing of product from the container. The interference fit yields to finger pressure to move the nozzle through the interference fit and return the lid to a closed position on the base of the closure.
In another form of two piece dispensing closure, the lid is circular and the end of the lid opposite the orifice contains two slots which mate with two posts extending upwardly from the surface of the base of the circular closure at its periphery. In this slot and post design, the posts are flexible and exposed, and are therefore subject to damage during handling of the closure or container. In addition, the lid is insecurely held in place, is subject to twisting and lateral movement, and is easily pulled from the posts when the lid is in the open position.
The closure of this invention is an improvement over these prior art closures.
It is a principal object of the invention to provide a two piece dispensing closure which has a hinge structure that provides a smooth peripheral symmetry, a planar top, and one which is less susceptible to damage than existing dispensing closures.
A further object to the present invention is the provision of a two piece dispensing closure which is simple in construction, pleasing in appearance and capable of a long, useful service life.
It is another object of the invention to provide a container closure in which the lid will remain in the open position and resist closing even when the container is inverted and vigorously shaken.
Another object of the invention is to provide a dispensing closure with a lid that remains in a stable working position without cracking or separating from the base.
It is yet another object of this invention to provide a closure in which there is an interference fit between the lid and the base as the lid is rotated to its fully open position, so that at least a perceptible finger pressure is required to move the lid to the closed position.
It is also an object of this invention to provide a dispensing closure which will permit the contents of the container to be secured from tampering after filing and which will have a smooth underside free from crevices and openings which may become contaminated.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.